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When to Plant Brussels Sprouts in Warren County, NJ

Warren County, New Jersey Zone 6b May

May in Warren County, New Jersey — your action list

May is a pivotal month for Warren County, New Jersey gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 16
Avg. first frost October 27
Soil temp (4") 61°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Start brussels sprouts indoors

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

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Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.

Warren County, New Jersey is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 27, giving you a growing season of approximately 194 days.

At an elevation of 369 feet, Warren County receives approximately 48.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Brussels Sprouts during the growing season.

Warren County, NJ (Zone 6b) Moderate season
194 days
Last Spring Frost April 16
194 growing days
First Fall Frost October 27
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Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: Jul 6 – Aug 31
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 16 – Sep 10
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Aug 8 – Oct 3

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Warren County

How your county's soil matches Brussels Sprouts's growing requirements.

Soil pH

Your soil pH (5.2–6.4) is more acidic than Brussels Sprouts prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Warren County is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Brussels Sprouts.

How to Plant Brussels Sprouts

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Brussels Sprouts

Brussels Sprouts needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Brussels Sprouts Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 3.9" 3.6" 0.3" 💧 Light watering
May 3.9" 3.9" 0" ✅ Rainfall sufficient
Jun 3.9" 4.2" 0" ✅ Rainfall sufficient
Jul 3.9" 4.4" 0" ✅ Rainfall sufficient
Aug 3.9" 4.3" 0" ✅ Rainfall sufficient
Sep 3.9" 4.7" 0" ✅ Rainfall sufficient
Oct 3.9" 4.3" 0" ✅ Rainfall sufficient
Nov 3.4" 0" ❄️ Dormant
Dec 4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Warren County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Brussels Sprouts Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Brussels Sprouts needs ~1,595 GDD — county provides 2,813 GDD Excellent fit

Brussels Sprouts Planting Timeline — Warren County, NJ

Brussels Sprouts Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 2 Apr 2 – Apr 23
Harvest July 16 Jul 16 – Sep 10
Fall Sowing August 18 Aug 18 – Sep 1

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May
June
July Harvest
August Fall Sowing Harvest
September Fall Sowing Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

90–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

194 days in Warren County

Growing Tips for Brussels Sprouts in Warren County

Direct sow Brussels Sprouts outdoors after April 16 in Warren County when soil has warmed and frost danger has passed.

Common pests for Brussels Sprouts in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 12-14 weeks before first fall frost. Stake tall plants to prevent toppling. Remove lower leaves as sprouts develop to improve air circulation.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Brussels Sprouts in Warren County, NJ?

Warren County is in Zone 6b with an average last frost of April 16. Plan your Brussels Sprouts planting based on this frost date — see the calendar above for exact timing.

What planting zone is Warren County, NJ?

Warren County, New Jersey is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 27.

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Your Warren County Garden Planner — Free

A 24-page printable planner built for Warren County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Warren County, NJ. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.